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Flashcards

Weeks Seven & Eight - Nervous System

Alex Betts English 53 cards

Cards in this deck (53)

  1. 1Action potentialElectrical impulse generated when membrane potential of a neuron reaches -55mV (threshold)
  2. 2Axon"Tail" of a neuron that extends from the cell body to another neuron (or effector cell). Can by myelinated or unmyelinated. Carries the action potential from where it's generated in the initial segment to the synaptic end bulbs at the end of axon terminals for it then to be transmitted.
  3. 3Cranial nerves12 pairs that are included in the PNS. They arise directly from brain stem. Cranial nerve X (Vagus nerve) is a mixed nerve that extends into thoracic & abdominal cavities.
  4. 4GangliaClusters of nerve cell bodies located outside the CNS, so within the PNS. They serve as relay points for transmitting sensory information and coordinating motor functions. Play a crucial role in integrating and processing signals within the PNS.
  5. 5MeningesThree protective layers that surround brain and spinal cord. From deep-superficial: Pia mater, Arachnoid mater, & dura mater. Around the brain, Dura mater consists of inner meningeal layer and outer periosteal layer. Subdural between D&A which contains non-csf fluid, & sub-arachnoid space between A & P which contains CSF.
  6. 6NerveAll information travels to CNS by nerves. Classified based on type of information they carry (CNS-organ = motor, organ-CNS = sensory, both ways = mixed).
    They're bundles of fibers made up of neurons that serve as the communication highways of the nervous system.
  7. 7Nodes of RanvierGaps in the Myelin sheath of myelinated axons where voltage gated channels are concentrated. They depolarise when an action potential is generated, allowing the impulse to "jump" down the axon (saltatory conduction). Hence, it travels faster down the axon.
  8. 8PNSConsists of cranial & spinal nerves, ganglia, enteric plexuses in small intestine, sensory receptors in skin. Sensory part of the nervous system that delivers information to the CNS and executes the response. Can be divided into Sensory (afferent) division & motor (efferent) division.
  9. 9ReflexFast response to a change in internal or external environment to try and restore homeostasis. Can be involuntary or voluntary & contralateral or ipsilateral.
  10. 10Spinal nerves31 pairs, including cervical, thoracic, lumbar, sacral, and coccygeal. Mixed nerves (sensory and motor) & except for thoracic, link together and form networks called plexuses (eg. sacral plexus etc.). Afferent neurons enter via posterior nerve root & efferent neurons exit via anterior nerve root
  11. 11SynapseSynaptic end bulb at end of axon terminals, releases neurotransmitters into synaptic cleft by exocytosis. They the diffuse across the cleft and bind to a ligand-gated channel, which then open to let positive ions into postsynaptic neuron.
  12. 12Synaptic cleftFluid filled space between synaptic end bulb of presynaptic neuron and postsynaptic neuron where neurotransmitters diffuse across and bind to ligand-gated channels, allowing them to open and let in positive ions.
  13. 13NREM sleepNon-rapid eye movement sleep, consists of N1, N2, and N3 sleep. N1 and N2 are light sleep and N3 is deep sleep. An average adult transitions through these stages multiple times in an average 8 hour sleep. Has slower neuronal activity, slower hr and rr, more regular hr and rr.
  14. 14Anterior rootIn spinal nerves, the motor (efferent) neurons leave via the anterior root.
  15. 15Axon terminalEnd of an axon where some are tipped with synaptic end bulbs. The action potential travels down the axon to the axon terminals before synapses occurs.
  16. 16DendritesShort, tapering, highly branched extension of Neuron cell bodies that receive stimuli from other neurons or sensory receptors.
  17. 17Grey matterCerebral cortex- comprised of cell bodies, dendrites, and unmyelinated axons. Responsible for processing information in the nervous system, including sensory perception, memory, and decision-making.
  18. 18MicrogliaType of neuroglia present in the CNS. They act as the brain's immune cells, helping to protect and support its function.
  19. 19NeurogliaNeuroglia and neurons make up nervous tissue. Neuroglia surround & support neurons, insulate them from each other, supply nutrients to promote neuron health and growth, & produce chemicals that guide young neurons to make connections. Divided into Schwann cells & satellite cells in PNS, and Ependymal cells, microglia, oligodendrocytes, and astrocytes in CNS.
  20. 20NucleusMain cell structure, contains all DNA and cell information. "command centre" of the cell.
  21. 21Postsynaptic neuronThe neuron that ligand-gated channels are attached to, receive the positive neurons as a result of neurotransmitters from presynaptic neuron binding to and opening these channels.
  22. 22Schwann cellType of neuroglia within PNS that forms the myelin sheath around axons of PNS neurons.
  23. 23StimulusChange in the internal or external environment which is measured by receptors and sent to CNS. Response is then carried out by PNS. Needs to take action potential to threshold of -55mV for action potential to be generated
  24. 24TractBundle of nerve fibers (axons) that are grouped together and carry signals from one part of the nervous system to another. Can transmit sensory information from the body to the brain (ascending tracts) or motor commands from the brain to the muscles (descending tracts).
  25. 25Saltatory conductionOccurs within myelinated axons, where the nodes of Ranvier depolarise when an action potential is generated, allowing for the action impulse to "jump" these gaps. Has the fastest nerve conduction velocity.
  26. 26Voltage gated channelsChannels within neuron membrane that don't open until a certain membrane potential has been reached (ie. Na+ channels open at -55mV). Main ones are Na+, Ca2+, and K+
  27. 27Circadian rhythmCircadian refers to any process in the body that occurs daily- processes can be biological biochemical, or behavioural. Needs to be synchronised to day/night cycle.
  28. 28Autonomic nervous system (ANS)Division of the PNS (specifically motor division). Responsible for visceral motor (involuntary) and conducts impulses from CNS to cardiac muscle, smooth muscle, and glands. Can be divided into sympathetic and parasympathetic nervous systems.
  29. 29CNSDivision of the nervous system that includes brain and spinal cord. Primary role is to integrate& analyse information and determine an appropriate response. Also houses control centres for feedback systems.
  30. 30Ependymal cellsType of neuroglia in CNS that line central cavities of the brain and spinal cord. Ciliated and they help with circulation of csf
  31. 31GyriElevated ridges within the brain formed by the outer layer called the cerebral cortex
  32. 32Motor neuronType of neuron that transmits signals from the cns to muscles or glands throughout the body (effector cells). These signals are responsible for initiating and controlling voluntary muscle movements, as well as regulating the activity of glands.
  33. 33NeuronsNeurons and neuroglia comprise nervous tissue. They're highly specialised cells that communicate by sending nerve impulses from one body part to another. Require a constant supply of O2 & glucose. Can be sensory (afferent) or motor (efferent).
  34. 34OligodendrocytesType of neuroglia within CNS that produce and maintain myelin. Act like Schwann cells except Schwann cells are found in PNS
  35. 35Presynaptic neuronNeuron that transmits the action potential down its axon towards the postsynaptic neuron. It's synaptic end bulbs release neurotransmitters by exocytosis that open the ligand-gated channels on postsynaptic neurons that allow an inflow of positive ions into the postsynaptic neuron.
  36. 36Sensory neuronAfferent neuron that receives the stimuli from sensory or visceral receptors and conduct impulses from these receptors to the CNS
  37. 37SulciGrooves between gyri in the brain
  38. 38VentriclesHollow, csf filled areas within the brain. Includes two lateral ventricles, the third ventricle, and the fourth ventricle. Fourth ventricle extends down into central canal of spinal cord. Ventricles are interconnected, there are choroid plexuses between them that produce csf.
  39. 39Continuous conductionOccurs within unmyelinated axons where the action potential is continuously propagated along the axon. Takes longer than saltatory conduction
  40. 40Leak channelsChannels within the neuron membrane (Na+ and K+) that are continuously leaky between repolarising and depolarising phases. There are more K+ channels and they are more "leaky" than Na+ so more K+ leaves the cell, helping it maintain a negative resting membrane potential
  41. 41Suprachiasmatic nucleus (SCN)Small region in the hypothalamus that serves as the body's primary biological clock, regulating the sleep-wake cycle and coordinating daily rhythms such as hormone secretion, body temperature, and metabolism.
  42. 42CSFLiquid found in and around brain and spinal cord that is formed from blood plasma within choroid plexuses. Circulates within the four ventricles in the brain and the central canal within the spinal cord. Functions include mechanical protection, maintenance of homeostasis, & circulation
  43. 43FissuresDeeper grooves (deeper than sulci) within the brain that separate larger regions. Longitudinal fissure separates left & right cerebral hemispheres; Lateral sulcus separates frontal & parietal lobes from the temporal lobe; Central sulcus separates frontal lobe from parietal lobe.
  44. 44InterneuronNeurons found in the CNS that act as connectors between sensory neurons and motor neurons. They relay signals between them, integrating and processing information.
  45. 45Myelin sheathFatty layer that surrounds most axons, broken up by nodes of Ranvier. Produced by oligodendrocytes in CNS and Schwann cells in PNS. Means action potential takes part in saltatory conduction
  46. 46NeurotransmittorLocated in synaptic vesicles in synaptic end bulbs. When Ca2+ voltage gated channels open and Ca2+ floods into synaptic end bulbs, it releases the vesicles into the synaptic cleft by exocytosis. The neurotransmitters diffuse across the cleft and bind to ligand-gated channels. Eg. serotonin and acetylcholine.
  47. 47Parasympathetic divisionDivision of the ANS that is involved in "rest and digest". Conserves energy and promotes house-keeping functions during rest. Functions include constricted pupils, constricted airways, and slow heartbeat.
  48. 48ReceptorSpecialized structure, typically located on the surface of a sensory neuron, that detects specific stimuli from the internal or external environment. Receptors convert stimuli into electrical signals that can be transmitted to the brain for processing and interpretation.
  49. 49Somatic nervous systemDivision of PNS (Specifically motor division) that controls voluntary motor movement. It conducts impulses from the CNS to skeletal muscles.
  50. 50Sympathetic divisionDivision of ANS that is involved with "fight or flight". It mobilises body systems during activity. Functions include dilated pupil, relaxed airways, and increased heartbeat.
  51. 51White matterArea of the brain deep to cerebral cortex and is comprised of myelinated axons which provide the white colour. Allows for the rapid transmission of information between different regions due to saltatory conduction occurring within these myelinated axons
  52. 52Autonomic toneContinuous, baseline level of activity in the ANS that helps maintain essential bodily functions, such as heart rate, within a normal range. Represents the balance between the sympathetic and parasympathetic divisions. Ensures that the body can respond appropriately to changes in internal & external conditions.
  53. 53REM sleepRapid eye movement sleep which occurs at the end of a sleep cycle. Has faster neuronal activity, irregular hr, paralysation of postural muscles, REM, and vivid dreams.

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Flashcards on Weeks Seven & Eight - Nervous System, created by Alex Betts on 02/05/2024.
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